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Mechanism Of Electroacupuncture On Improving Mild Cognitive Impairment In SAMP8 Mice Through The NLRP3/Caspase-1 Pyroptosis Signaling Pathway

Posted on:2023-03-28Degree:MasterType:Thesis
Country:ChinaCandidate:Y LiFull Text:PDF
GTID:2544306803980829Subject:Basic Theory of TCM
Abstract/Summary:PDF Full Text Request
Objective:This study investigates the effects of electroacupuncture at "Baihui" and "Zusanli" on learning and memory in SAMP8 mice,and further elucidates the possible mechanism of electroacupuncture acting on the NLRP3/Caspase-1classical pyroptosis signaling pathway.At the same time,provide experimental basis for clinical use of electroacupuncture in the treatment of patients with mild cognitive impairment.Methods:In this study,male SAMP8 mice aged 7 months were selected as the research object,and SAMR1 mice of the same month and same genetic background were selected as the blank control group.Adaptive feeding was conducted for 7 days before formal intervention.Morris water maze test was then adopted to screen all mice,and those without symptoms related to cognitive impairment were excluded.30 SAMP8 mice meeting the standard were selected.According to the principle of random allocation,10 mice in each group were divided into model group,2Hz EA group and 10 Hz EA group,and 10 SAMR1 mice were in the blank group.Referring to the "Acupuncture Acupuncture Point Atlas of Laboratory Animals",the positions and acupuncture methods of "Baihui" and "Zusanli" points were specified.and sparse-dense waves were selected,with the current of 1 m A and the frequency of 2 Hz/10 Hz,each lasting 30 min and once a day for 14 days.Except for the electroacupuncture treatment group,the other two groups received the same degree of grasping and immobilization at the same time period every day to reduce the deviation of experimental data caused by animal stress.After the EA intervention ended,the mice were tested with the Morris water maze to evaluate the cognitive ability of each group.Samples of hippocampal tissue and serum were collected for further evaluation after cognitive function assessment.Neuropathological staining was performed by HE staining,and dead cells were stained with the terminal deoxynucleotidyl transferase-mediated d UTP nick-end labeling(TUNEL)method.Enzymelinked immunosorbent assays(ELISAs)were used to detect the serum levels of IL-1β,IL-6,IL-18 and TNF-α.Western blot was used to detect the expression levels of NLRP3,ASC,Caspase-1,GSDM-D,IL-1β,IL-18,Tau and Aβ.Results:Morris Water maze:(1)location navigation test: compared with blank group,the latency of escape and total activity of mice in model group were significantly longer(P<0.01);After 14 days of EA treatment,compared with the model group,the escape latency and total swimming distance of mice in2 Hz EA and 10 Hz EA groups were significantly decreased(P<0.01),but there was no significant difference in improvement degree between THE 2Hz EA and 10 Hz EA groups(P>0.05).(2)Space exploration experiment: compared with blank group,the number of crossing platform in model group was significantly reduced(P<0.01);Compared with model group,The Times of crossing platform in 2Hz EA group and 10 Hz EA group were significantly increased(P<0.01),and there was no significant difference in improvement degree between A 2Hz group and 10 Hz EA group(P>0.05).HE staining: the neurons in hippocampus CA1 and CA3 of SAMR1 mice in the blank group were intact,clear and orderly.Compared with the blank group,the Neuronal cells in CA1 and CA3 area of hippocampus in model group showed obvious lesions in volume,shape and arrangement,mainly showing sparse Neuronal cells,unclear cell boundaries,increased cell body swelling,accompanied by obvious nuclear shrinkage.Compared with model group,the pathological changes in hippocampal CA1 and CA3 regions of mice in 2Hz EA group and 10 Hz EA group were relieved to some extent,and the hippocampal neurons of mice in 10 Hz EA group were arranged in an orderly manner,with clear cell boundaries and fewer neurons with abnormal morphology and structure,and the improvement was significant.TUNEL staining: Compared with blank group,the number and proportion of dead cells in hippocampus CA1 and CA3 of SAMP8 mice in model group were significantly increased(P<0.001);Compared with the model group,the number and proportion of dead cells in CA1 and CA3 hippocampal regions of2 Hz EA and 10 Hz EA groups were significantly decreased(P<0.01),and the number and proportion of dead cells in THE 10 Hz EA group were significantly improved(P<0.05).ELISA test: compared with blank group,serum levels of inflammatory factors TNF-α,IL-6,IL-18 and IL-1β in model group were significantly increased(P<0.001);After 14 days of EA treatment,the levels of 4inflammatory factors decreased significantly(P<0.001 or P<0.01);The levels of IL-6 and IL-1β in the 10 Hz EA group were significantly lower than those in the 2Hz EA group(P<0.05).Western blot analysis: compared with blank group,the protein expression levels of Aβ,NLRP3,ASC,Caspase-1,IL-18,IL-1β and GSDM-D in model group were significantly increased(P<0.001).After 14 days of acupuncture,compared with the model group,the protein expression levels of NLRP3,Caspase-1,GSDM-D,IL-1β and IL-18 in 2Hz EA group were significantly decreased(P<0.001);Compared with model group,the expression of NLRP3,ASC,Caspase-1,GSDM-D,IL-1β and IL-18 was decreased in 10 Hz EA group(P<0.001).Compared with 2Hz EA group,NLRP3,ASC,Caspase-1,IL-1β and IL-18 were significantly down-regulated in 10 Hz EA group(P<0.05 or P<0.01).There was no significant difference in the expression of Aβ and Tau protein in the hippocampus of 2Hz ES and 10 Hz EA groups(P<0.05).Conclusions:1.Electroacupuncture of "Baihui" and "Zusanli" can effectively improve the learning and memory ability of SAMP8 mice,reduce neuropathological damage in hippocampal CA1 and CA3 regions,and reduce inflammatory mediators IL-1β 、 IL-6 、 IL-18 and TNF-α in serum of MCI mice level,down-regulated the protein expression levels of NLRP3、 ASC、 Caspase-1、GSDM-D、 IL-1β、 IL-18 in hippocampus.2.The mechanism of electroacupuncture "Baihui" and "Zusanli" interfering with mild cognitive impairment in SAMP8 mice may be by inhibiting the inflammatory response mediated by the NLRP3/Caspase-1pyroptosis signaling pathway,thereby inhibiting the pyroptosis of hippocampal neurons cells to improve cognitive function.
Keywords/Search Tags:Baihui(GV20), Zusanli(ST36), Electroacupuncture, Mild cognitive impairmen, Pyroptosis
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